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 <head>

  <title>CSS Test: transparency of margin area and background-color</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
  <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#mpb-examples" title="8.2 Example of margins, padding, and borders" />
  <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background" title="14.2 The background" />
  <link rel="match" href="../reference/ref-filled-green-100px-square.xht" />

  <meta content="" name="flags" />
  <meta content="The margin area of an element is always transparent. The background-color of an element never paints its own margin area. The background-color of an element only paints its own border area (if any), its own padding area (if any) and its own content area (if any). Therefore the background-color of the content area (and of the padding area, if any, and of the border area, if any) of a parent element shines through the margin area of its child. In this test, div#parent is painted green and is 100px by 100px; its sole child has an 99px margin bottom and a 100px margin right margin which are transparent and through which we can see the background color of its parent." name="assert" />

  <style type="text/css"><![CDATA[
  p {margin: 1em 0em;}

  div#parent
  {
  background-color: green;
  height: 100px;
  width: 100px;
  }

  div#child
  {
  background-color: red;
  height: 1px;
  /*
  'height: 1px' is set intentionally so that the
  top margin (16px) and bottom margin (99px) of such child
  box do not collapse through the element.
  */
  margin: 16px 100px 99px 0px;
  /*
  'margin-top: 16px' correspond to the margin-bottom of the
  <p>. The margin-top of the child box collapses with the
  margin-top of div#parent and then the collapsed margin-top
  of div#parent then collapses in its turn with the
  margin-bottom of the <p>.
  */
  width: auto;
  }
  ]]></style>

 </head>

 <body>

  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

  <div id="parent">
    <div id="child"></div>
  </div>

 </body>
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